首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   258篇
  免费   45篇
  国内免费   66篇
测绘学   6篇
大气科学   88篇
地球物理   77篇
地质学   135篇
海洋学   16篇
天文学   3篇
综合类   14篇
自然地理   30篇
  2024年   1篇
  2023年   2篇
  2022年   1篇
  2021年   2篇
  2020年   6篇
  2019年   9篇
  2018年   13篇
  2017年   6篇
  2016年   15篇
  2015年   4篇
  2014年   16篇
  2013年   37篇
  2012年   11篇
  2011年   12篇
  2010年   17篇
  2009年   13篇
  2008年   12篇
  2007年   10篇
  2006年   19篇
  2005年   12篇
  2004年   13篇
  2003年   13篇
  2002年   13篇
  2001年   16篇
  2000年   13篇
  1999年   16篇
  1998年   12篇
  1997年   8篇
  1996年   13篇
  1995年   7篇
  1994年   5篇
  1993年   11篇
  1992年   2篇
  1991年   3篇
  1990年   4篇
  1989年   1篇
  1984年   1篇
排序方式: 共有369条查询结果,搜索用时 46 毫秒
131.
The potential of Clean Development Mechanism (CDM) projects to deliver pro-poor benefits at the community level is examined. Both regular CDM and premium add-on standard projects are evaluated, including the Gold Standard and Climate, Community and Biodiversity (CCB) Standard, through the use of seven poverty indicators. Some key characteristics associated with providing pro-poor benefits are also identified. Finally, the market potential of a revised or new premium add-on standard explicitly designed to deliver pro-poor benefits is assessed through the use of a survey. The results indicate that regular CDM projects are only moderately successful at delivering pro-poor benefits. Although the few projects registered that utilize the CCB Standard all performed well in delivering pro-poor benefits, those that used the Gold Standard performed only slightly better than regular CDM projects. Characteristics associated with providing pro-poor benefits include the use of add-on standards, a high level of stakeholder participation, and the development of projects by not-for-profit and government/intergovernmental organizations. The survey of carbon market participants indicated both an interest and desire for Certified Emission Reduction (CER) credits with pro-poor benefits attached and shows that the market potential for such a standard to be quite good.

Policy relevance

This analysis of the CDM goes beyond sustainable development to consider the potential of a project to deliver pro-poor benefits at the local community level. Specific characteristics associated with projects are identified that appear to deliver pro-poor benefits that may benefit future project design. Through this analysis and identifying these characteristics, actions may be taken to incorporate those into CDM project requirements or guidelines to advance the mechanism as a means to contribute to poverty alleviation.  相似文献   
132.
Yang Liu 《Climate Policy》2013,13(6):767-783
This study assesses the effectiveness of a mix of policy instruments including the Clean Development Mechanism (CDM) and the Feed-in Tariff (FIT) to induce wind technology diffusion in China. Relying on a panel dataset consisting of information from 1207 CDM wind projects in thirty provinces over the period 2004–2011, the empirical analysis indicates that: first, wind energy deployment responds primarily to those counterfactual emissions which would have occurred in the absence of the wind projects; second, the dynamic efficiency of the FIT subsidy shows a potential incompatibility with the CDM incentive; third, the leverage of the CDM on wind investment is supported by the industry and technology policy package, which explains in large part the decrease in the FIT subsidy. Given these findings, suggestions are made regarding the design of a future carbon offset scheme and its link with mitigation action in developing countries.  相似文献   
133.
《Climate Policy》2013,13(3):242-254
The Clean Development Mechanism (CDM) under the Kyoto Protocol allows industrialized countries to use credits from greenhouse gas (GHG) abatement projects in developing countries. A key requirement of the CDM is that the emission reductions be real, measurable and additional. This article evaluates how the additionality of CDM projects has been assessed in practice. The analysis is mainly based on a systematic evaluation of 93 registered CDM projects and comes to the conclusion that the current tools for demonstrating additionality are in need of substantial improvement. In particular, the application of the barrier analysis is highly subjective and difficult to validate in an objective and transparent manner. Key assumptions regarding additionality are often not substantiated with credible, documented evidence. In a considerable number of cases it is questionable whether the emission reductions are actually additional. Based on these findings, practical recommendations for improving the assessment of additionality are provided.  相似文献   
134.
Technology transfer is often mentioned as an ancillary benefit of the Kyoto Protocol's Clean Development Mechanism (CDM), but this claim has hardly been researched or substantiated. The question of technology transfer is important, both for developing countries in need for new technology and knowledge and for industrialized countries, as it provides export potential for climate-friendly technologies. To determine what technology transfer means, whether it is occurring through the CDM, and what the value of the associated capital flows is, this article examines technology transfer in the 63 CDM projects that were registered up until 1 January 2006. Technology hardware originates from outside the host country in almost 50% of the evaluated projects, particularly in non-CO2 greenhouse gas projects, wind energy projects, and a substantial share of the hydropower projects. Bioenergy and projects in the agricultural sector mainly use local technology. The investment value associated with the CDM projects that transferred technology is estimated to be around €470 million, with about €390 million coming from the EU. As the non-CO2 greenhouse gas projects had very low capital costs, the investment value was highest in the more capital-intensive wind energy and hydropower projects. We also found substantial soft technology transfer, but uncertainties for this finding are greater.  相似文献   
135.
东北地区浅源中强震及深震与西太平洋板块俯冲   总被引:10,自引:0,他引:10  
本文研究了1990年以来东北地区的浅源中强震和深震的相关关系,还讨论了板块俯冲对东北地区的影响,结果表明,东北地区浅源地震与深源地震存在着相关活动的特点。  相似文献   
136.
雷电流通过人体的物理学机理研究   总被引:1,自引:0,他引:1  
本文从人体的导电特性、雷电流的特征以及雷电流对人体的作用机制等几个方面,提出了一些人体遭受雷击的内在和外部影响因素,从人体通过雷电流的物理机理上试图解释当人体遭雷击,甚至是一个人群遭雷击时,有些人死亡,有些人受伤,有些人则健好如故的原因。  相似文献   
137.
The research and achievements made on seismic subsidence of loess, obtained over the past 30 years, were reviewed. Seismic Subsidence of Loess (SSL) has been verified by microstructure characteristics, dynamic triaxial experiments, and in-situ explosion tests, and has become an important subject in the field of seismic loess engineering research. While, the research is still in the stage of theoretical study of saturated soil, and there are no representative cases of seismic subsidence of loess in historical earthquakes. It is difficult to express structure characteristics using microstructure morphology. While, soil mechanics are available methods for this. Seismic subsidence judgment is absolute in some certain value ranges for several parameters. Therefore, probabilistic judgment should be developed. The seismic subsidence ratio is estimated mostly by empirical formulas or semi- empirical and semi-theoretical formulas, which are based on laboratory data. These formulas are not established on the basis of physical process and mechanics of seismic subsidence, and this leads to more variables, complicated computation, and poor practicability. To solve these problems, we need to distinguish the main factors and corresponding variables, to establish a mechanics model for seismic subsidence estimation, and to characterize its physio-mechanical process. The key of anti-seismic subsidence treatment is to reduce the seismic subsidence property of soils, and to lower the interaction between the soil body and underground structures.  相似文献   
138.
余震活动机理研究综述   总被引:3,自引:2,他引:1  
曲均浩  蒋海昆 《中国地震》2012,28(2):109-120
从介质和应力的不均匀性、力学加载、流体侵入及应力腐蚀、速率-状态依从等几方面对余震活动机理研究进行综述.已有的研究表明,介质和应力的不均匀性是余震产生的基本前提.瞬时蠕变和余滑观点能够从力学的角度解释震后极短时间内余震的快速衰减,而应力松弛过程更有利于解释长时期的余震活动特征.流体侵入及应力腐蚀在一定条件下控制着余震的演化过程.受主震应力扰动影响的断层间的相互作用,始终存在于余震的活动过程之中.各类模型和理论解释都在努力寻求与G-R关系和修改的大森公式这两个统计地震学基本关系的一致性.  相似文献   
139.
以1933年岷江上游叠溪地震诱发的地面地质灾害基本特征入手,系统阐述了叠溪地震区斜坡变形破坏分区分带的 典型特征,归纳总结了高地震烈度区斜坡变形破坏的空间发育分布规律;重点从斜坡变形破坏分区特征与发震机制和应力场 的成生关系方面,分析探讨了叠溪地震区斜坡变形破坏分区特征的成因机制,阐明了1933年叠溪地震造成震区不同区带斜坡 变形破坏类型和变形破坏强烈程度差异之原因,充分揭示了内生地质作用对浅表生地质灾害的控制作用。  相似文献   
140.
物理过程参数化方案的不确定性是目前气候系统模式不确定性的重要来源之一.随着模式内在复杂度攀升,模拟场景多样化,参数化方案中基于先验的和人工的物理参数选取方法已经逐步成为限制模式模拟能力的瓶颈之一.为此,本文设计并提出了初选与寻优相结合的两步法参数优化方案.初选阶段用全因子采样方法对不确定参数空间进行初始敏感性分析,估计最优解所在区域;寻优步采用单纯型下山法,基于初选阶段确定的参数组合快速寻优.将两步法应用于中国科学院大气物理研究所(英文缩写:IAP)大气科学和地球流体力学数值模拟国家重点实验室(英文缩写:LASG)格点大气模式第2版:GAMIL2,选取其深对流方案和云量方案中的3个重要参数开展寻优,优化以综合减小模式降水、风场、温度、湿度、位势高度以及辐射通量的误差为目标.这些变量用GAMIL2标准版本标准化后形成单一的目标.结果显示,优化后的目标函数值比GAMIL2标准版本改进了7.5%.机理分析表明,调优后的参数优化了大气中的水汽凝结作用,进而减少模式的湿度偏差,改进云量的模拟效果;同时水汽凝结作用的变化通过大气内部动力和热力相互作用及响应影响温度、位势高度和风场的模拟.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号